The x amount of heads tall has nothing to do with someone's actual length, only the proportion of the body.A realistic grown human is about 7-8 heads tall, however anime characters are often 6-7 heads tall.

Btw, you also took the bit of hair sticking out while measuring the head, hair doesn't count. o_o

You can see the reference head sukieblackmore drew compared to the tip of the hair. Also, even if it's just 2 inches when you multiply it 7 times over it easily passes a foot. Realistically I'd say he's around 7.5 to 8 heads, which is more likely for a young adult male.